Решите квадратные уравнения: а)3x^2-4x-5=0 б)3x^2-4x-1=0

Найдем корешки уравнений через дискриминант.

а) 3 * x - 4 * x 5 = 0;

D = b - 4 * a * c = (-4) - 4 * 3 * (-5) = 16 + 12 * 5 = 16 + 60 = 76;

x1 = (-(-4) + 76)/(2 * 3) = (4 + 76)/6 = 4/6 + 76/6 = 2/3  + 2/6 * 19 = 2/3 + 1/3 * 19;

x2 = (4 - 76)/6 = 4/6 2 * 19/6 = 2/3 1/3 * 76.

б) 3 * x^2 4 * x 1 = 0;

D = (-4) - 4 * 3 * (-1) = 16 + 12 = 28;

x1 = (4 + 28)/(2 * 3) = (4 + 28)/6 = (4 + 2 * 7)/6 = 4/6 + 2/6 * 7 = 2/3 + 1/3 * 7;

x2 = (4 - 28)/6 = 2/3 1/3 * 7.